Issue 6037: MutableSequence.__iadd__ should return self.

diff --git a/Lib/_abcoll.py b/Lib/_abcoll.py
index 73966dbce6b65bd5e842b23b6caf41ee15436f9b..16d85b44dc9b23b384947c180681da38ed557e32 100644 (file)
--- a/Lib/_abcoll.py
+++ b/Lib/_abcoll.py
@@ -595,6 +595,7 @@ class MutableSequence(Sequence):
 
     def __iadd__(self, values):
         self.extend(values)
+        return self
 
 MutableSequence.register(list)
 MutableSequence.register(bytearray)  # Multiply inheriting, see ByteString